﻿#region LicenseHeader

// Copyright 2012 The Trustees of Indiana University.  All rights reserved.
// 
// The Indiana University licenses this file to you under the Apache License, 
// Version 2.0 (the "License"); you may not use this file except in compliance 
// with the License.  You may obtain a copy of the License at 
// 
// http://www.apache.org/licenses/LICENSE-2.0
// 
// Unless required by applicable law or agreed to in writing, software 
// distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
//  WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.  
// See the License for the specific language governing permissions and 
// limitations under the License.
// 
// @author Thilina Gunarathne (tgunarat@indiana.edu)

#endregion

using System;
using System.Collections.Generic;
using System.Linq;
using AzureMRCore;
using AzureMRCore.DataTypes;
using AzureMRCore.MapRed;
using Microsoft.WindowsAzure.ServiceRuntime;

namespace KMeansMRSample
{
    internal class KMeansMerge :
        Merger<IntKey, DoubleVectorValue, IntKey, MatrixValue<double>, IntKey, MatrixValue<double>>
    {
        public override int Merge(IDictionary<IntKey, List<DoubleVectorValue>> values, string programArgs,
                                  List<KeyValuePair<IntKey, MatrixValue<double>>> dynamicData,
                                  IOutputCollector<IntKey, MatrixValue<double>> collector,
                                  ReduceContext reduceContext, out bool addIteration)
        {
            double[][] output = new double[dynamicData.First().Value.BlockHeight][];
            foreach (var value in values)
            {
                output[value.Key.Key] = value.Value.First().Value;
            }
            MatrixValue<double> matrixValue = MatrixValue<double>.GetInstance(output,
                                                                              dynamicData.First().Value.BlockHeight,
                                                                              dynamicData.First().Value.Width, 0, 0);

            int numIterations = 10;
            string configString = RoleEnvironment.GetConfigurationSettingValue("KMeansNumIterations");
            if (configString != null & configString != "")
            {
                numIterations = Int32.Parse(configString);
            }
            collector.Collect(IntKey.GetInstance(0), matrixValue);
            addIteration = Int32.Parse(reduceContext.ReduceTask.PartitionKey) < (numIterations - 1);
            return 0;
        }
    }
}